Browsing by Author "Wang, SH"

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A complexity aware variable-bit-depth motion estimation
(2005)
Wang, SH
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Wang, CN
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Chiang, TH
;
電子工程學系及電子研究所
;
Department of Electronics Engineering and Institute of Electronics
Demands for using different complexity level algorithms to deliver multimedia content delivery over portable devices are increasing thanks to advanced battery technology. This paper describes a novel complexity aware motion estimation for H.264 based on pixel representation of different bit-depth and a simple scene change detection module. The experimental results show that with identical searching complexity, improvement on averaged PSNR is more than 0.2dB for 4-bit representation and more than 2 dB for 1/2-bit representation as compared to conventional bit-truncation method.
A flux estimation method for a permanent-magnet synchronous motor
(2004-11-01)
Wang, SH
;
Fang, CH
;
Lin, SK
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電控工程研究所
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Institute of Electrical and Control Engineering
This paper deals with the flux estimation of a permanent-magnet synchronous motor (PMSM). Contrary to the conventional no-load test, the proposed method needs no extra servomotor. It is simply to drive the PMSM in a single-phase mode with the currents large enough to make the PMSM rotate in the same direction. Under such a condition, the flux of the PMSM can be easily estimated. (C) 2004 Elsevier B.V. All rights reserved.
A platform based bus-interleaved architecture for de-blocking filter in H.264/MPEG-4 AVC
(2005-02-01)
Chang, SC
;
Peng, WH
;
Wang, SH
;
Chiang, T
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電子工程學系及電子研究所
In this paper, we proposed a platform based bus-interleaved architecture for the de-blocking filter in H.264. Specifically, to efficiently use the bus bandwidth, we classify the filtering mode into 8 types and use an adaptive transmission scheme to avoid redundant data transfer. Moreover, to reduce the processing latency, we use a bus-interleaved architecture for conducting data transmission and filtering in parallel. As compared to the state-of-the-art designs, our scheme offers 1.6x to 7x performance improvement. While clocking at 100MHz, our design can support 2560x1280@30Hz processing throughput. The proposed design is suitable for low cost and real-time applications. Moreover, it can be easily applied in system-on-chip design.
A platform-based de-blocking filter design with bus-interleaved architecture for H.264
(2005)
Chang, SC
;
Peng, WH
;
Wang, SH
;
Chiang, TH
;
交大名義發表
In this paper, we present an ARM platform-based architecture design for de-blocking filter in H.264. According to statistical analysis, we propose an adaptive transmission scheme to reduce the bus workload. Moreover, we develop a bus-interleaved architecture to reduce the processing latency. As compared to the state-of-the-art designs, our scheme offers 3x to 14x performance improvement. Furthermore, we have proved our design using an ARM emulation board.
A platform-based MPEG-4 Advanced Video Coding (AVC) decoder with block level pipelining
(2003)
Wang, SH
;
Peng, WH
;
He, YW
;
Lin, GY
;
Lin, CY
We present a baseline MPEG-4 AVC (Advanced Video Coding) decoder based on an optimized platform-based design methodology. With this methodology, we jointly optimize the software and hardware design of the decoder. Overall decoding throughput is increased by synchronizing the software and the dedicated co-processors. The synchronization is achieved at macroblock-level pipelining. In addition, we optimize the decoder software by enhancing the frame buffer management, boundary padding, and content aware inverse transform. To speed up motion compensation and inverse transform, which are the most computationally intensive modules, two dedicated acceleration modules are realized. For comparison, the proposed prototype decoder and MPEG-4 AVC reference decoder are evaluated on an ARM platform, which is one of most popular portable devices. Our experiments show that the throughput of the MPEG-4 reference decoder can be improved by 6 to 7 times. On an ARM966 board, the optimized software without hardware acceleration can achieve a decoding rate up to 5 frames per second (fps) for QCIF video sequences. With the dedicated accelerators, the overall throughput is increased by about 30% to reach 6.6 fps on the average and is up to 10.3 fps for slow motion video sequences.
A software-hardware co-implementation of MPEG-4 Advanced Video Coding (AVC) decoder with block level pipelining
(2005-08-01)
Wang, SH
;
Peng, WH
;
He, YW
;
Lin, GY
;
Lin, CY
We present a baseline MPEG-4 Advanced Video Coding (AVC) decoder based on the methodology of joint optimization of software and hardware. The software is first optimized with algorithm improvements for frame buffer management, boundary padding, content-aware inverse transform and context-based entropy decoding. The overall decoding throughput is further enhanced by pipelining the software and the dedicated hardware at macroblock level. The decoder is partitioned into the software and hardware modules according to the target frame rate and complexity profiles. The hardware acceleration modules include motion compensation, inverse transform and loop filtering. By comparing the optimized decoder with the committee reference decoder of Joint Video Team (JVT), the experimental results show improvement on the decoding throughput by 7 to 8 times. On an ARM966 board, the optimized software without hardware acceleration can achieve a decoding rate up to 5.9 frames per second (fps) for QCIF video source. The overall throughput is improved by another 27% to 7.4 fps on the average and up to 11.5 fps for slow motion video sequences. Finally, we provide a theoretical analysis of the ideal performance of the proposed decoder.
Anomalous substrate current in polycrystalline silicon thin-film transistors
(2003)
Zan, HW
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Chen, SC
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Wang, SH
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Chang, CY
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電子工程學系及電子研究所
In this paper, the substrate current of polycrystalline silicon thin-film transistors was measured and investigated the first time. With typical T-gate pattered structure, an abnormal high substrate current was found while devices were operated under high gate voltage. This is generated from the parasitic tunnelling current between the n+ inversion region and the p+ body region. Under lower gate voltage, substrate current generated from impact ionization effect is also observed and characterized. After extracting fitting parameters from the device characteristics, a simple physically-based model was established and compared with the measured results. A plausible grain boundary scattering effect was included in the proposed model. Good agreements were found through a wide range of gate bias and various drain bias, verifying the validity of this unified model.
Axial load behavior of stiffened concrete-filled steel columns
(2002-09-01)
Huang, CS
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Yeh, YK
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Liu, GY
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Hu, HT
;
Tsai, KC
This study investigates the axial load behavior of concrete-filled steel tubular (CFT) columns with the width-to-thickness ratios between 40 and 150, and proposes an effective stiffening scheme to improve the mechanical properties of square cross-sectional CFT columns. Seventeen specimens were tested to examine the effects of cross-sectional shapes, width-to-thickness ratios, and stiffening arrangements on the ultimate strength, stiffness, and ductility of CFT columns. Moreover, nonlinear finite element analysis was also conducted to investigate cross-sectional axial stress distribution at the ultimate strength. Comparing the measured ultimate strength with estimates by using some current specifications suggested that current specifications may considerably underestimate the ultimate strength of circular CFT columns, particularly for columns with a small width-to-thickness ratio. Results in this study demonstrate that the proposed stiffening scheme can significantly enhance the ultimate strength and ductility of square CFT columns.
Blind watermarking using wavelet tree quantization
(2002)
Wang, SH
;
Lin, YP
;
電子工程學系及電子研究所
;
Department of Electronics Engineering and Institute of Electronics
This paper proposes a blind watermarking scheme using wavelet tree quantization. The wavelet coefficients of the host image are grouped into wavelet trees and each watermark bit is embedded using two trees. The trees are so quantized that they exhibit a large enough statistical difference; which will later be used for watermark extraction. Each watermark bit is embedded in all frequency bands, which renders the mark more resistant to attacks that remove certain frequency components. Also, the embedding is spread throughout a relatively large spatial region, which yields more robustness against spatial domain geometric attacks. Examples of various attacks will be given to demonstrate the robustness of the proposed technique.
Collection efficiency and capacity of three samplers for acidic and basic gases
(2001-06-15)
Tsai, CJ
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Huang, CH
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Wang, SH
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環境工程研究所
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Institute of Environmental Engineering
This paper compares the collection efficiency and capacity of a coated porous metal disk with those of a silica gel tube and an impinger at the acid or basic aerosol concentration of two times the permissible exposure limitation (Taiwan IOSH, Institute of Occupational Safety and Health), relative humidity of 80 +/- 5%, and temperature of 30 +/- 3 degreesC in the laboratory. Using 5% sodium carbonate/glycerin coating, the collection efficiencies of the porous metal disk for nitric acid, hydrogen chloride, and hydrogen fluoride are found to be higher than those of the silica gel tube and the impinger when the sampling time is less than 3.0 h. The gas collection capacity of the porous metal disk coated with 5% sodium carbonate is calculated to be 3.9, 5.8, and >2.5 mg for nitric acid, hydrogen chloride, and hydrogen fluoride, respectively. For ammonia, the porous metal disk coated using 4% citric acid performs slightly better than the impinger, and the corresponding capacity is slightly greater than 33.6 mg.
Computing motif correlations in proteins
(2003-12-01)
Horng, JT
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Huang, HD
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Wang, SH
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Chen, MY
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Huang, SL
Protein motifs, which are specific regions and conserved regions, are found by comparing multiple protein sequences. These conserved regions in general play an important role in protein functions and protein folds, for example, for their binding properties or enzymatic activities. The aim here is to find the existence correlations of protein motifs. The knowledge of protein motif/domain sharing should be important in shedding new light on the biologic functions of proteins and offering a basis in analyzing the evolution in the human genome or other genomes. The protein sequences used here are obtained from the PIR-NREF database and the protein motifs are retrieved from the PROSITE database. We apply data mining approach to discover the occurrence correlations of motif in protein sequences. The correlation of motifs mined can be used in evolution analyses and protein structure prediction. We discuss the latter, i.e., protein structure prediction in this study. The correlations mined are stored and maintained in a database system. The database is now available at http://bioinfo.csie.ncu.edu.tw/ProMotif/. (C) 2003 Wiley Periodicals, Inc.
Design and testing of a personal porous-metal denuder
(2001-07-01)
Tsai, CJ
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Huang, CH
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Wang, SH
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Shih, TS
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環境工程研究所
A personal denuder made of porous-metal disc has been designed and tested. The entire casing and substrate support are made of Teflon, and the sampling flow rate is 2 L/min. The sampler consists of a two-stage cascade impactor (having cut-off aerodynamic diameters of 9.5 and 2.0 mum, respectively) to collect liquid particles and two porous-metal discs (diameter: 2.54 cm; pore size: 100 mum; thickness: 0.317 cm) to collect basic and acidic gases, respectively. The denuder was tested for gas collection efficiency and capacity at a gas concentration of two times the permissible exposure limit (PEL, promulgated by Taiwan Institute of Occupational Safety and Health (IOSH)), with relative humidity (RH) of 80 +/- 5% and temperature of 30 +/- 3 degrees C. The test data indicate that the gas collection efficiency is high, and the capacity is sufficient for the acidic/basic gas sampling in the workplace. Using 5% (w/v, g/mL) sodium carbonate/1% (w/v) glycerol coating on the porous-metal disc, the collection efficiency is 91.2 +/- 0.26% (average +/- standard deviation), 95.08 +/- 0.06% and 100 +/- 0.04%, and the capacity is 4.47, 7.2, and 2.5 mg for HNO3, HCl and HF, respectively. The collection efficiency for NH3 for the porous-metal disc with 4% (w/v) citric acid coating is 96.39 +/- 0.13%, and the capacity is 33.6 mg.
Expression, characterization, and purification of recombinant porcine lactoferrin in Pichia pastoris
(2002-06-01)
Wang, SH
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Yang, TS
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Lin, SM
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Tsai, MS
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Wu, SC
Recombinant porcine lactoferrin (rPLF) was synthesized in Pichia pastoris using a constitutive promoter from the glyceraldehyde-3-phosphate dehydrogenase gene. Strains expressing rPLF with its own signal sequence or with that from the yeast alpha-mating factor (alpha-MF) were able to produce and secrete rPLF, but levels were consistently higher using alpha-MF constructs. In contrast, P. pastoris strains that expressed rPLF without a signal sequence produced the protein in an insoluble intracellular form. Increasing the initial pH of shake-flask culture medium from 6.0 to 7.0 or adding ferric ions to the medium (to 100 muM) resulted irk significant improvements in expression of rPLF from P. pastoris. Expression levels (approximately 12 mg/L) were much higher than those observed from Saccharomyces cerevisiae strains (1-2 mg/L). P pastoris-secreted rPLF was isolated and purified via a one-step simple procedure using a heparin column. The molecular size (78 kDa), isoelectric point (8.8-9.0), N-terminal amino acid sequence, and iron-binding capability of rPLF were each similar to that of native milk PLF. (C) 2002 Elsevier Science (USA).
Expression, characterization, and purification of recombinant porcine lactoferrin in Pichia pastoris
(2002-03-20)
Mao, SJT
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Wang, SH
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生物科技學系
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Department of Biological Science and Technology
Expression, characterization, and purification of recombinant porcine lactoferrin in Pichia pastoris
(2002-03-20)
Mao, SJT
;
Wang, SH
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生物科技學系
;
Department of Biological Science and Technology
Platform based design of all binary motion estimation (ABME) with bus interleaved architecture
(2005)
Wang, SH
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Tao, WL
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Wang, CN
;
Peng, WH
;
Chiang, T
This paper presents an efficient hardware-software implementation with a marcoblock based pipelining and a bus interlaced architecture for all binary motion estimation (ABME), which has been proven to be simple and low cost for hardware design. The bus interleaved preprocessing module of the ABME architecture can generate downsampling and binarized data in the same flow without additional dedicated hardware. With the 3-layer binary bitplane of ABME, we use a two-dimensional (2-D) mapping unit and a binary adder tree instead of a systolic array to compute the block matching metric, which is sum of difference (SoD), in one cycle. In addition, a new bus bandwidth reduction scheme is proposed by reusing the binarized image, which can achieve up to 67% bus bandwidth saving. The experiment shows that for each macroblock, our design can finish ABME within 283 cycles with 65k gate counts synthesized by UMC 0.18 um cell library.
Wavelet tree quantization for copyright protection watermarking
(2004-02-01)
Wang, SH
;
Lin, YP
;
電子工程學系及電子研究所
;
Department of Electronics Engineering and Institute of Electronics
This paper proposes a wavelet-tree-based blind watermarking scheme for copyright protection. The wavelet coefficients of the host image are grouped into so-called super trees. The watermark is embedded by quantizing super trees. The trees are so quantized that they exhibit a large enough statistical difference, which will later be used for watermark extraction. Each watermark bit is embedded in perceptually important frequency bands, which renders the mark more resistant to frequency based attacks. Also, the watermark is spread throughout large spatial regions. This yields more robustness against time domain geometric attacks. Examples of various attacks will be given to demonstrate the robustness of the proposed technique.